高剪切应力诱导引发乙丙橡胶与马来酸酐官能化反应的研究

Functionalization of ethylene-propylene rubber with maleic anhydride in the melt state through high shear stress-induced initiation

采用在熔融挤出过程中提高双螺杆挤出机螺杆转速的高剪切应力诱导引发方法和采用添加引发剂与提高螺杆转速的应力诱导复合引发方法,研究了乙丙橡胶(EPR)与马来酸酐(MAH)的官能化反应;采用化学分析、熔体流动速率测定、FT IR、SEM观测和材料力学性能测试等方法考察了官能化产物(EPR-g-MAH)性能及其对PA66/EPR-g-MAH共混材料力学性能的影响。结果表明:双螺杆挤出机的螺杆转速和官能化反应温度对产物的接枝(嵌段)率和熔体流动速率具有重要影响;与热引发方法相比较,270℃条件下螺杆转速由80 r/m in提高至800 r/m in时,产物的接枝(嵌段)率由0.26%提高至0.47%;与引发剂引发方法相比较,产物熔体流动速率由每10 m in约0.07 g提高至1.80 g,抑制或避免了官能化过程中的交联副反应;所得产物的接枝(嵌段)率和熔体流动速率易于控制,对于PA66的增韧作用,存在最佳接枝(嵌段)率(约0.66%)和最佳熔体流动速率(每10 m in约2.0 g)。

The functionalization reactions of ethylene-propylene rubber （ EPR ） with maleic anhydride （ MAH ） in melt state through the high shear stress-induced initiation by increasing the screw rotation speed of twin-screw extruder and through a compounded initiation by adding a certain initiator and increasing the screw rotation speed were studied. The effects of the functionalized products on the mechanical properties of the PA66/EPR-g-MAH blends were investigated. The results show that the influences of the screw rotation speed of twin-screw extruder and the reaction temperature on the percentage of grafting and melt flow rate of the functionalized products are very important. Comparing with the product obtained by thermal initiation, the percentage of grafting of the stress-induced products increases from 0.26% to 0.47% when the screw rotation speed increases from 80 r/min to 800 r/min at 270 ℃ ; comparing with the product though peroxide initiation, the melt flow rate of the compounded initiated products increases from 0. 07 g/10 min to 1.8 g/10 min when the screw rotation speed increases from 80 r/min to 800 r/min at 210 ℃, the crosslinking reaction can be suppressed or prevented, and the percentage of grafting and melt flow rate of the functionalized products can be easily controlled through adjusting the screw rotation speed of twin-screw extruder and the reaction temperature. In addition, it was found that for toughening PA66, there is the optimum percentage of grafting （ about 0. 66% ） and the optimum melt flow rate （ about 2. 0 g/10 min） of the functionalized product, where the impact strength of the PA66/EPR-g-MAH （80/20） blend reaches to 91.6 kJ/m^2.